“I think it opens up the portal more widely on the whole character issue,” said one senior Republican strategist granted anonymity to speak candidly. “If this were one incident of domestic strife it would one thing but this demonstrates a pattern so I think it could be really bad.”

Throughout the race, Gingrich has been open about his personal foibles, which include an extramarital affair with his current wife, Callista, while still married to Marianne.

Asked today about the allegations made by his second wife, Gingrich called them “tawdry and inappropriate”. And, in a statement released by the campaign, Gingrich’s two daughters from his first marriage said: “The failure of a marriage is a terrible and emotional experience for everyone involved. Anyone who has had that experience understands it is a personal tragedy filled with regrets, and sometimes differing memories of events. ...We will not say anything negative about our father’s ex-wife. He has said before, privately and publicly, that he regrets any pain he may have caused in the past to people he loves.”

Polling done last month suggested that most voters didn’t care much about Gingrich’s personal life. Almost three-quarters (72 percent) in a December Washington Post-ABC News poll said Gingrich’s “marital history” made no difference in their vote; four percent said it made them more likely to vote for him, 19 percent said it made them less willing to cast a ballot for the former House Speaker.

At issue is whether voters will regard Marianne Gingrich’s comments as largely old news delivered by someone with whom the former Speaker has no relationship or whether her allegations will lead to a re-examination of his personal life.

The former analysis could actually help Gingrich, turning him into something of a sympathetic figure. We saw that sort of scenario play out in South Carolina in 2010 when gubernatorial candidateNikki Haley was hit by allegations of an extramarital affair. She fought back aggressively and instead of it hurting her campaign, it strengthened it.

The latter scenario could be far more problematic for Gingrich who has done everything he can to put the past in the past and keep it there. The South Carolina primary electorate is the most conservative and religiously-tinged of any of the first three states and headlines about Gingrich and “open marriage” could well dull the momentum he has clearly been building in the state over the past few days.

“It’s really bad, not just the story itself but the fact that it will remind GOP voters that Gingrich is a little bit nutty,” said one senior Republican operative not currently aligned in the presidential race. “It elevates the concerns about nominating him because or being erratic and unstable.”

(One other x-factor working against Gingrich is that the Drudge Report, an influential news tip sheet, has bet hugely on the Marianne Gingrich story; there are no fewer than 10 headlines on the site related to the “open marriage” allegations.)

Which direction the story heads depends, according to conversations with a variety of Republican strategists, largely on how voters in South Carolina ultimately view Marianne Gingrich.

Is she a vengeful ex-wife trying to dredge up old news to exact some sort of payback? Or is she a rightly aggrieved woman speaking out about a man she knows intimately well in hopes of providing the full picture to voters before Saturday?

“I don’t think there is any new news,” said one GOP consultant. “It really comes down to how believable a messenger she appears.”